Conceive

Not necessarily. My last period started on 1st May (Tuesday), my fiancé and I had sex twice about 10 days later (11th and 12th) and I got a positive pregnancy test 2 weeks later (Sunday 27th). My next period was due the 29th and obviously never came. My period tracker estimated that I should’ve ovulated Tuesday 15th. My temps had been off all month so I’m not sure when I actually ovulated, but my cycle is normally pretty regular 26-28 days, which means I should’ve had two periods that month.

If your period was due may 1 and it didn’t come yes you conceived in April. I’m not sure your using the word conceive right. That would be the day egg and sperm combined to form a baby. It also doesn’t necessarily have to be the day you had sex. Sperm can survive for several days afterwards. My daughter was “conceived” days after my husband went out of town for work but we had sex the night before he left.

You don’t usually conceive immediately following sex, it takes a few days for the little swimmers to meet up with your egg in your Fallopian tube, and another few days for the fertilized egg to travel down and implant. When you ovulate can also drastically change when you conceive.

Here’s my details for an example:

I typically have 28-30 day cycles. I had my first day of my last period on April 26. I’m like 90% sure that the sex I had on May 12 resulted in my pregnancy (and I’m positive it didn’t happen before then because I hadn’t had sex). May 12 would have been Day 16 of my cycle. I took my first test on Day 25 and it was negative, but got a clear positive on Day 28. My guess is my egg was probably fertilized around Day 17-19, and didn’t implant until around Day 23 (which I suspect I was having implantation cramping on).